Rosaceae: Rosoideae - achenes
Achenes are dry, indehiscent fruits (fruitlets) that in Rosaceae subfamily
Rosoideae may develop enclosed by a fleshy hypanthium (arrow A, top row, right;
in a hooked hypanthium in Agrimonia)
or on an enlarged floral receptacle, as in Fragaria (arrow, bottom row,
left). In both these cases the resulting fruit is an aggregate of achenes (all
developed from the pistils of a single flower with an apocarpous gynoecium).
|Top row, left; Rosa fruit in longitudinal section, achenes enclosed in fleshy hypanthium, © R. Joos. Top row, right; Rosa fruit in longitudinal section (A, achene; S, styles filling hypanthium neck). Note that fruit has been occupied by insect larvae. Photo: R. C. Evans © 1998 R. C. Evans. Bottom row, left; Fragaria virginiana fruits with achenes (arrow) on surface of enlarged receptacle.|
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© 2008 Department of Ecology & Evolutionary Biology and 2000-2006 Botany Department, University of Toronto.